Biological processes are often enhanced by multiple interactions between two entities, or multivalency. Antibody function, for example, is modulated through structural flexibility and high-avidity binding. Toward a better understanding of avidity and flexibility in antibody recognition, we pose the question, "Is there a range of separation between epitopes that maximizes the avidity of antibody recognition?" We hypothesize that there is, and we propose a plan of investigation. Multivalent antigens with epitopes placed at controlled distances will be synthesized and deposited onto self-assembled monolayers on gold. The affinities for monovalent and bivalent antibody binding to these surfaces will be measured as a function of the distance between epitopes using surface plasmon resonance spectroscopy. The presence or absence of an optimal distance range would provide useful information to basic biochemistry concerning the importance of flexibility in multivalent antibody recognition. If an optimum is found, numerous applications become possible, including better design of inhibitors, better affinity purification methods, and higher sensitivity detectors.